DL180G5 / P400 cable & 12bay backplane connections

[Niels Svennekjaer]

When I got my DL180G5 it was "born" with an 12Bay backplane (460001-001), but the controller did only had one multi SATA/SAS cable (361316-006) connecting the controller and backplane, so to get the last 4 drives working, an secondary cable must be purchased..

This is NOT "just" an extra 361316-006 (sp# 389952-001), as someone in HP support did tell (I did purchase one).. because there is no free connectors on the back of the backplane for the large connector.

So can anyone tell me what part no the missing cable has, and where to plug it in on the backside of the 12bay backplane?

Is there somewhere an document/manual telling how the backplane works and what all the free plugs are for ? (have been searching, but not found anything)

Sspecially there are two free sata/sas connectors and when connecting a sas DVD there the P400 controler detects it, but I cant seem to use it

Also it seems that there can be pluged more than 8 drives (like 10) into the backplane, and the OS (linux) can use them.. but only 8 can be active at the time.. can anyone tell more about this ?

[TTr]

The server quickspecs state that for a 12-drive option you need a controller such as the P400 that can support expanders.

http://h18000.www1.hp.com/products/quickspecs/12400_na/12400_na.html

The P400 has 8 SAS ports and as is it can support 8-drives only. There are two x4 connectors on the P400 for 4+4 drive ports. What kind and how many connectors are available on the drive backplane (disk cage)?

If there are 3 SAS connectors on the disk backplane, you can not use all 12 drives with the P400. Either you need a SAS expander card http://h18000.www1.hp.com/products/quickspecs/13232_div/13232_div.html or a second controller.

If there are only two connectors, there may be a SAS expander built in to the drive backplane. You need to try again with firmware upgrades etc. What exactly did you mean when you said that up to 10 drives can be connected?

or a second controller.

[Niels Svennekjaer]

The P400 from the link is the one I have.. (as picture, no extra mem or battery)

I had 10 physical drives installed in the bays, and when booting, the controller firmware (inside the controller BIOS setup) did see all 10 drives, and when booting in Linux, it looked like that Linux could see all 10 also, but when trying to access the drives, it was like there was some kind of big delay (secs) for writing data on one drive and another.. (and the 10'th)

The system was ordered as an 470084-766 CTO (special offer) and the backplane have "only" following connectors
- one of the connectors like the two on top of the P400
- one 14 pins plug (like mail part of the old flat-cable connectors)
- one 10 pins plus (like mail part of the old flat-cable connectors)
- two normal S-ATA connectors

I have just checked, the backplane IS a 460001-001 (I have to dismounted the backplane to look at the lable..)

That is also why I ask for more documentation for the 460001-001 backplane

[TTr]

> the controller firmware (inside the controller BIOS setup) did see all 10 drives,

I assume this was the P400 BIOS screen. If so this means that the disk backplane has a builtin SAS expander and the P400 sees all disks. Have you upgraded all the firmware to the latest? The slowness may be a driver issue with Linux.

I don't have this server and unfortunately HP has a generic "ML100 series" user guide which does not cover the latest G4 and G5 series features and details.

Whatever it is the P400 has 8 sas ports. So if they are spread out to all 12 drive bays, there is some kind of SAS expander circuitry in the disk backplane. How many cables go from the P400 to the backplane?

[Niels Svennekjaer]

the P400 & backplane have just (after my previous test) been firmware upgraded.

On the backplane there is a chip with large cooling rips like the on on the drawing of the extender board..

I just collected a lot of sata disks and plugged into the system, and the P400 BISO sees all.

I did setup a new 4x160G Raid 5 for test..

and did boot in CentOs.. I ran some test from hpacucli (attached), and it looks like all 12 disks are accessible.. BUT ?

If the P400 is only a 8 disk controller, and the backplane have an embedded extender board.. will all 12 disk be usable, or only 8 at the time ? ( for my logic, there somehow should be added at least 4 channels, but there is no plug for it at the backplane)

And the 10 point Q is of curse, what do I have to purchase to get the last 4 drives running at optimal speed. (several calls/mails to HP didnt help)

[TTr]

So it looks like that the 12-disk backplane has a built-in SAS expander.
The SAS expander is very similar to a LAN switch. there is switching taking place from the controller ports to the disk slot ports.

> If the P400 is only a 8 disk controller, and the backplane have an embedded extender board.. will all 12 disk be usable

All 12 disks are usabel via the switching mechanism.

> what do I have to purchase to get the last 4 drives running at optimal speed.

Nothing. You have no direct access to the disk slot ports. You have to go through the expander.

How many data connections do you have from the P400?

[Niels Svennekjaer]

After have been reading the quickspec and googling a lot, I found this tw page http://wiki.osslab.org.tw/Hardware/Storage/Enterprise/HP_DL180_G5 where they show the my model of the backplane (use google translate for an language of your choice)

Reading the texts, the P400 in my configuration should support the 12 drives without any extra stuff(and maybe up to 18/28 drives depending how the expanders are used)

The chip on the back was an expander chip.

Pictures:

Full 12 bay backplane: http://wiki.osslab.org.tw/@api/deki/files/1053/=%2525E8%2525AA%2525BF%2525E6%252595%2525B4%2525E5%2525A4%2525A7%2525E5%2525B0%25258FP1010595.JPG

SFF-8484 connector: http://wiki.osslab.org.tw/@api/deki/files/1055/=%2525E8%2525AA%2525BF%2525E6%252595%2525B4%2525E5%2525A4%2525A7%2525E5%2525B0%25258FP1010597.JPG

Power connectors: http://wiki.osslab.org.tw/@api/deki/files/1056/=%2525E8%2525AA%2525BF%2525E6%252595%2525B4%2525E5%2525A4%2525A7%2525E5%2525B0%25258FP1010598.JPG

(hope this will also help other, because, it seems the usage / documentation of the backplane (46000-1-001) is a secret)

[TTr]

Take a look at the service/maintenance guide on page 44.

http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c01365016/c01365016.pdf

It appears that the 12 disk backplane has only one SAS cable connector which would indicate that only 4 controller ports are connecting to the 12 disks giving you a 3:1 ratio of controller to disk switching.
Not sure what the #5 connectors are used for. They may single device passthrough connectors.

The 8-disk backplane on page 43, has two SAS connectors so you get a direct connection from the 8 controller ports to the the 8 disks (no switching).